Coupling end reinforcement for flexible conduit



March 1l, 1969 M- H, GOLDENBERG 3,431,948

COUPLING END REINFORCEMENT FOR FLEXIBLE CONDUIT Original Filed March 3,1964 lll' " pill FIG United States Patent O 3,431,948 COUPLING ENDREINFORCEMENT FOR FLEXIBLE CONDUIT Malvin H. Goldenberg, 27 Phipps Lane,Plainview, NX. 11803 rignal application Mar. 3, 1964, Ser. No. 349,090,now Patent No. 3,324,893, dated June 13, 1967. Divided and thisapplication Apr. 13, 1967, Ser. No. 652,357 U.S. Cl. 138-109 3 ClaimsInt. Cl. F161 9/00, .7l/00 ABSTRACT F THE DISCLOSURE A reinforcement fora flexible conduit. The flexible conduit includes a tubular Wall whichis flexible and fluid-tight and reinforced along its length againstradial collapse during bending of the conduit. One end of the conduit isadapted to be connected with a relatively rigid tubular component withrespect to which the conduit is to be flexed. The reinforcing meanswhich strengthens the end portion of the conduit which is coupled tothis component is in the form of a tubular reinforcing structuretelescoped with the tubular wall of the flexible conduit and extendinginwardly from the end of the conduit. The tubular reinforcing means hasan outer end situated at the end of the conduit and an inner endsituated within the flexible conduit, and the tubular reinforcing meanshas a wall whose thickness decreases gradually from its outer toward itsinner end.

This is a division of application Ser. No. 349,000, filed Mar. 3, 1964,now U.S. Patent No. 3,324,893.

This invention relates to flexible Iconduits such as used forfluid-tight transfer of fluids including gases and liquids, and arrangedto have one or both ends coupled with a relatively rigid tubularcomponent with respect to which the conduit is adapted to be flexed.More particularly, the present invention is directed to an improvedreinforcing means strengthening the end portion of the conduit coupledto such a component against weakening and breaking of the relativelyflexible tubular wall of the conduit.

Flexible conduits are used extensively for fluid transfer with bothliquids and gases. Among other applications where flexible conduits havefound wide use are as the hoses of vacuum cleaners, and as the-connections of oxygen devices and respiration devices, air compressorsystems, cooling systems, and other like uses.

To provide flexibility as well as fluid-tight impermeability for thefluid being transmitted, the relatively elongated tubular walls of suchconduits have been made of relatively flexible fluid-tight material suchas, for example, plastic composition materials, rubber, or rubberlikematerials. Various arrangements have been used for radially reinforcingsuch conduits to prevent restriction of the conduit when it is bent, orto prevent radial collapse thereof during flexing or bending of theconduit. For example, some conduits are provided with interior orexterior reinforcements of metallic wire or plastic of various crosssections. The metallic wire may be bare or it may be coated with othermetals, or with rubber, plastic, plastic composition material, orrubber-like material. These considerations apply where a separatereinforcing member is used for the tubular wall of the conduit.

Other reinforcing arrangements have also been used. For example, theflexible tubular wall has been formed by helically or spirally windingrubber, plastic composition material, or rubber-like material of suchcross sec- 3,431,948 Patented Mar. 11, 1969 lce tion that the completedconduit will maintain its tubular body. Further arrangements include theuse of corrugations formed in the body of the conduit for the purpose ofmaintaining the tubular form against radial collapse during flexing ofthe conduit.

As stated, one or both ends, and usually both ends, of such flexibleconduits are arranged to be coupled to a relatively rigid component suchas, in the case of a vacuum cleaner, the blower outlet or inlet at oneend of the flexible conduit and a suction or blowing nozzle at the otherend of the flexible conduit. Due to the fact that this combinationrepresents a relatively flexible member, such as the flexible conduit,coupled to a relatively rigid component, a problem of weakening andbreaking of the wall of the flexible conduit is introduced due to thefact that the greatest stresses occur at or immediately adjacent theconnection of the relatively flexible conduit to the relatively rigidcomponent.'For this reason, various arrangements have been proposed formodifying the construction of flexible conduits adjacent or at the endsthereof. Such reinforcing arrangements have taken various forms,including closer spacing of reinforcing members, closer spacing ofcorrugations, the use of a heavier or thicker reinforcing or conduitwall at the ends, or the addition of a separate end reinforcing member.While the reinforcing or strengthening arrangements used hitherto havereduced breakage and weakening to some extent, it has been recognizedthat a substantial i-mprovement in reinforcing or strengthening of theends of flexible conduits is needed.

Specifically, with present end reinforcing arrangements, the greateststress is con-centrated over a relatively narrow annular area of theflexible conduit or of the reinforcement. Thus, if the end reinforcementis relatively flexible, the greatest strain occurs at the zone where theflexible conduit is joined to another less flexible component of thesystem. On the other hand, if the end reinforcement is less flexible ormore rigid, the greatest strain is at the inner end of thereinforcement. In other cases, all of the strain occurs or isconcentrated in one relatively narrow annular area of the flexibleconduit or of the reinforcement.

In accordance with the present invention, an improved end reinforcingmeans for a flexible conduit is provided in which the stresses occurringbetween two members of different flexibility, such as the relativelyflexible wall of the conduit and a relatively less flexiblereinforcement telescoped therewith, is distributed over a substantialaxial length of the flexible conduit and of the reinforcement. Thus, thestress concentration is gradually diminished in a direction away fromthe zone of engagement between a more flexible element and a lessflexible element. This provides greatly improved protection againstbreakage or weakening of the flexible wall of the conduit at or near theends or points o-f attachment thereof to relatively rigid or relativelyless flexible components of the system with which the flexible conduitis used.

Thus, and with the present invention, the stress occurring at theconjunction of two members of different flexibility is distributed overa much wider annular area of the conduit, as over several convolutionsof the conduit wall in the event that the latter is spirally orhelically wound, or over several convolutions of a conduit reinforcementwhere a spiral or helical reinforcement is used with the flexibleconduit.

For an understanding of the principles of the invention, reference ismade to the following description of typical embodiments thereof asillustrated in the accompanying drawings. In the drawings:

FIGS. l and 2 are axial sectional views through flexible conduitsrepresentative of presently used prior art constructions for reinforcingthe coupling ends of flexible conduits; and

FIGS. 3 through 6 are similar views illustrating flexible conduitsembodying the invention.

Referring first to the prior art construction shown in FIGS. 1 and 2,FIG. 1 illustrates a flexible conduit 1l) embodying a relativelyelongated tubular wall 11 of relatively llexible fluid-tight material.The wall 11 is provided with reinforcing means for preventing radialcollapse thereof during flexing or bending of the conduit 1li. Theparticular reinforcing means shown in FIG. 1 comprises a spiralreinforcement of wire or plastic indicated at 12. An outer covering 13is provided over the flexible wall 11, although this may be omitted ifdesired.

In accordance with known prior art practice, the end of conduit 16`which is to be coupled to a relatively rigid component, such as a nozzleor the like, is additionally reinforced inwardly from such end, and thisadditional reinforcement is, in the case of prior art arrangements, atubular member 15. Tubular member may be more flexible than flexiblewall 11 and, in such case, the stress will be concentrated at the verynarrow annular zone where the flexible conduit 1G` is in engagement withthe end of the relatively rigid nozzle or the like. On the other hand,and if reinforcement 15 is more rigid or less flexible than wall 11, thegreatest concentration of stress on the flexible wall 11 will occur atthe inner end of reinforcement 15 and again in a very narrow annularzone. As stated, while reinforcement 15 provides some protection againstweakening and breakage of the wall of flexible conduit 10, thereinforcement against weakening or breakage is not suflicient and it isdesirable that an improved reinforcing means be provided.

FIG. 2 illustrates a variation of this prior art arrangement, and thesame reference characters, primed have been used to designate partscorresponding or identical with those of FIG. 1. The difference of thearrangement in FIG. 2 is that the end reinforcing sleeve or tubular wallmeans 15' is disposed between the flexible wall 11 and its outercovering 13, rather than interiorly of the spiral reinforcement 12. Thisprior art arrangement has exactly the same defects `from the standpointof effectively inhibiting weakening and breakage of the wall of theexible tubing as does the arrangement of FIG. l.

FIG, 3 illustrates a conduit of the type shown in FIG. 1 but providedwith an end reinforcement in accordance with the present invention.Thus, the flexible conduit 2f) of FIG. 3 includes a relatively elongatedflexible tubular wall 21 which is reinforced against radial collapse bya spiral rein-forcement 22 and which has an outer covering 23. It shouldbe understood, in the following discus sion of FIGS. 3, 4, 5 and 6,that, while a spiral type of reinforcement has been illustrated, this issolely by way of example in that the invention is fully applicable toflexible conduits having other means providing reinforcement againstradial collapse or flattening of the flexible conduit during bendingthereof.

In accordance with the present invention, that end )of conduit which isarranged to be coupled to a relatively rigid component, or both ends ofthe conduit 20, has inserted therein a relatively elongated tubularreinforcing means so that the latter is telescoped with the flexibletubular wall 21 and extends inwardly from the end `of the conduit. Inaccordance with the invention, the inner portion of the tubular endreinforcing means 25 decreases, in effective wall dimensions measureddiametrically of conduit 20, from a diametric plane outwardly of theinner end of the tubular reinforcing means 25 to a minimum at the innerend of the latter` In the arrangement of FIG. 3, this is effected byproviding the inner end of tubular reinforcing means 25 with a bias cutedge 26. Due to the -bias cut of inner end 26, the bending stresseswhich could occur at the junction between two parts, 21 and 25, ofdifferent flexibility, are distributed over a axially elongated annulararea of the tubular wall 21 and over several convolutions of the spiralreinforcement 22.

FIG. 4 illustrates an arrangement which is essentially similar, insofaras the conduit construction is concerned, to that 'of FIG. 2, but whichincludes an end reinforcing member 25 which is identical with the endreinforcing member 25 of FIG. 3. In this case, as in FIG. 2, the endreinforcing member 25 is disposed between the flexible tubular wall 21and its outer covering 23' rather than being disposed interiorly of thereinforcing 22 as in FIG. 3. The results, insofar as the distribution ofstresses over a relatively axially elongated annular area of theflexible conduit 20', and particularly of the flexible tubular wall 21',are the same as in the arrangement of FIG. 3.

FIGS. 5 and 6` illustrate an alternative arrangement of the endreinforcing member whereby the mentioned effect of `decreasing theeffective wall dimensions, measured diametrically of the conduit, of theend reinforcing member, and from the `diametric plane outwardly of theinner end thereof to a minimum at the inner end thereof can be attained.Thus, and referring particularly to FIG. 5, the end reinforcing member3() decreases in thickness inwardly from its outer end to its inner endso that, in effect the cross section of the wall of member 30 is taperedin thickness as indicate-d at 31. Thus, the cross sectional area of thewall and thus the effective wall dimensions measured diametrically ofthe conduit 20, decrease in an inward direction. In this particularinstance, the stress concentration occurring between two members, suchas 21 and 3l) of different flexibility, is distributed over the fullaxial length of the reinforcing member 30. The reinforcing member 30could, for example, be molded before insertion into the conduit 20.

FIG. 6 illustrates an arrangement, equivalent to that of FIG. 5, inwhich a reinforcing member A35 is constructed by wrapping a triangularsection of thin material on a mandrel so as to provide a tapered insert.The reinforcing member 35 is provided =with the several convolutions 36which give a net tapered effect to the reinforcing member as indicatedby the sloping inner edge 37. Again, as in FIGS. 3, 4 and 5, the walldimensions of the tubular reinforcing means 35 decrease, as measureddiametrically of conduit 20, from the outer end of the reinforcing means35 to the inner end thereof.

It will be apparent that modification of the end reinforcements 25, 25',30 and 35 could be made, such as the provision of ribs, flutes, annularconvolutions and helical convolutions. Furthermore, the tubularreinforcing means could be incorporated as an integral part of thematerial of conduit 20 or 20 by varying the thickness o r flexibility atthe points where reinforcement is desired. Strips of reinforcingmaterial may be used, rather than a single piece, in order to attain theobjectives of the invention.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

1. In a flexible conduit including a relatively elongated tubular wallof relatively flexible fluid-tight material reinforced throughout itslength against radial collapse during bending of the conduit andarranged to have at least one end coupled with a relatively rigidtubular component with respect to which the conduit is adapted to beflexed: improved reinforcing means strengthening the end portion of theconduit coupled to said component against weakening and breaking of saidrelatively flexible tubular wall, said reinforcing means comprisingrelatively elongated tubular reinforcing means telescoped with saidtubular wall, having an outer end situated at said one end of saidflexible conduit and extending inwardly from said end of said conduit toterminate at an inner end opposed to said outer end, the Wall of saidtubular reinforcing means decreasing in thickness from its outer end toits inner end.

2. In a flexible conduit, improved and reinforcing means, as claimed inclaim 1, in which said tubular reinforcing means is an integralone-piece member inserted into said conduit.

v3. In a exble conduit, improved and reinforcing means, as claimed inclaim 1, in which said tubular end reinforcing means comprises atriangular strip wrapped around a mandrel to provide overlappingconvolutions in which the wall thickness decreases from the outer end ofthe tubular reinforcing Imeans to the inner end thereof.

References Cited UNITED STATES PATENTS 513,318 1/1894 Grimm 13S- 1091,175,373 3/1916y Noack 138-109 2,882,072 4/1959 Noland 138-109 X3,073,352 1/1963 `Bay 13S-109 X HENRY S. IAUDON, Primary Examiner.

U.S. Cl. X.R. 138-134

